Antibacterial composition containing 2,6-diaminophenyl penicillin or salt thereof



United States Patent 3,551,569 ANTIBACTERIAL COMPOSITION CONTAINING2,6-DIAMINOPHENYL PENICILLIN OR SALT THEREOF Peter Baumann, Fullinsdorf,Basel-Land, and Markus Zimmermann, Riehen, near Basel, Switzerland,assignors to Geigy Chemical Corporation, Greenhurgh, N.Y., a corporationof Delaware No Drawing. Original application Aug. 30, 1965, Ser. No.483,827. Divided and this application Mar. 26, 1969, Ser. No. 833,225 gInt. Cl. A61k 21/00 US. Cl. 424-271 4 Claims ABSTRACT OF THE DISCLOSUREAntibacterial compositions comprising 2,6-diaminophenyl penicillin or asalt thereof, and a carrier.

CROSS REFERENCE This is a division of Ser. No. 483,827, filed Aug. 30,1965.

DETAILED DESCRIPTION This relates to new chemo-therapeutically valuablepenicillin derivatives.

Penicillins such as benzyl penicillin (=Penicillin G) or phenoxymethylpenicillin (:Penicillin V), which have been known for a considerabletime, have proved to be very'effective for the treatment of infectionscaused by gram positive bacteria. They have the disadvantage, however,that they are ineffective against the so-called penicillin resistantstrain Staphylococcus aureus which cause the enzymepenicillinase.

However, now that 6-amino-penicillanic acid as the basic structure ofall penicillins has become accessible, attempts have been made to findnew, 'semisynthetic penicillins which are effective against theresistant strains of Staphylococcus aureus, 2,6-dimethoxyphenylpenicillin (Methicillin), which has been on the market for aconsiderable time, has this property. However, it suffers from thedrawback that it is not absorbed via the gastro-intestinal tract, it isnot stable in the presence of acid and has a limited range of action;thus itsmode of application and its range of application are limited.

It has now surprisingly been found that 2,6-diaminophenyl penicillin, ofthe fromula and its pharmaceutically acceptable salts with inorganic andorganic bases have excellent antibacterial activity against grampositive and some gram negative bacteria. 2,6-diaminophenyl penicillinhas a broad range of action hitherto unknown for penicillins in that itis both active against resistent Staphylococci life Methicillin butthat, at the same time, it is also effective against gram-negativebacteria, showing an activity in this respect which is similar to thatof Arnpicillin. Arnpicillin itself has no effect on resistantStaphylococci; Methicillin, on the other hand, has none againstgram-negative bacteria.

2,6-diaminophenyl penicillin and its salts are produced by knownmethods, but in the work-up and salt formation, the hybrid ionproperties of the end product should be borne in mind.

In order to obtain 2,6-diaminophenyl penicillin, 6- amino-penicillanicacid or a salt thereof is reacted with an acid halide, anhyd'ride orazide or' with an activated ester of an acid of the general formulaPatented Dec. 29, 1970 ice wherein A represents the amino group or agrouping containing nitrogen which grouping can be converted into anamino 10 group by catalytically activated hydrogen, to form a 6-acylamino penicillanic acid (aryl penicillin) of the general formula l Son -OONII-- -o1 r i 1 A |N I o 0 0 0 (III) wherein A has the meaninggiven above and the latter or a salt thereof is converted to2,6-diarninophenyl penicillin or a basic salt thereof while convertingthe grouping A into the amino group by catalytically activated hydroen.g

To produce salts with organic bases, for example those given below, thesodium or potassium 6-acylamino penicillanate can be reacted, e.g., withthe free acids in organic solvents or the alkali salts of the acids canbe brought together with salts of the organic bases, e.g., thehydrochlorides, in water and the salts which precipitate can be isolatedand dried.

Salts of 2,6-diaminophenyl penicillin according to the invention whichcan be produced in this manner are, for example, the sodium, potassium,ammonium, magnesium or calcium salts, or salts of organic bases such asdiethylamine, triethylamine, diethanolamine, N-ethyldiethanolamine,pyrrolidine, piperidine, N-ethyl-piperidine,1-(fi-hydroxyethyl)-piperidine, morpholine, procain, benzylamine,di-benzylarnine, 1-phenylpropyl-(2)-amine and other amines which areoften used for the production of penicillin salts.

The following nonlimitative examples illustrate the inyention further.The temperatures are given therein in degrees Centigrade.

EXAMPLE 1 (a) 1.0 g. of 2,6-dinitrobenzoic acid is dissolved in 5 ml. ofthionyl chloride and the solution is refluxed for 30 minutes. The excessthionyl chloride is evaporated in vacuo, the residue is dissolved inbenzene and the benzene solution boiled down. The residue is dried for 1hour in vacuo. The resulting crude acid chloride is used for thefollowing reaction.

(b) 1.16 g. of 86.1% 6-amino-penicillanic acid are suspended in 30 ml.of anhydrous chloroform and 2 ml. of triethylamine and the suspension isstirred for 30 minutes at room temperature (20). The solution isfiltered and the filtrate cooled to 0. The acid chloride, dissolved in10 ml. of chloroform, is then added dropwise within 5 minutes and thereaction mixture is stirred for 1 hour at room temperature. The clear,pale yellow solution is boiled down in a rotary evaporator (water bathtemperature 35) and the residue is dissolved in 30 ml. of water and ml.of methylisobutyl ketone. The pH of the aqueous phase is adjusted to 2.1with 10 N sulphuric acid while stirring and the phases are separated.The aqueous phase is extracted with 5 ml. of methylisobutyl ketone. Themethylisobutyl ketone extracts are combined, washed with 5 ml. of waterand dried with sodium sulphate. The methylisobutyl ketone solution isthen extracted with sufiicient 3% sodium bicarbonate solution to impartto the aqueous phase a pH of 6.8-7.0. The phases are separated and theorganic phase is again extracted with ml. of water. The combined aqueousphases are washed with 25 ml. of ether and freed from dissolved ether ina rotary evaporator. The clear and almost colourless solution of2,6-dinitrophenyl penicillin sodium obtained in this way is evaporatedat a low temperature under high vacuum or lyophilised. The product, awhite voluminous powder, shows in the IR spectrum (potassium bromide) astrong band at 565p which is typical of the fl-lactam ring.

(c) In order to reduce the nitro groups of the lastmentioned compound,2.7 g. of the latter are dissolved in 150 ml. of distilled water and thesolution is hydrogenated with 1.5 g. of palladium on charcoal (5% Pd) atroom temperature and slight excess hydrogen pressure. Hydrogenabsorption ceases completely after about 3 to 4 hours. Up to this point,841 ml. of hydrogen have been absorbed which corresponds to 6 moles foreach equivalent weight of 2,6-dinitrophenyl penicillin.

The solution is then filtered and lyophilised whereupon2,6-diaminophenyl penicillin sodium remains as a pale grey amorphouspowder. In the IR spectrum the powder shows the characteristic bands forthe lactam ring at 5.65p..

(d) Bacteriological properties of 2,6-diaminophenyl penicillin sodiumobtained according to (c) and illustrated by the following:

In the incorporation test, the minimal concentrations which inhibitvarious Staphylococcus strains are:

Concentration Staphylococcus strainin ,ug./ml. Aureus Geigy 5002 (r) l0Aureus Geigy 5005 (r) Lactia NCTC 8340 (s) 0.1-1 Aureus Smith (s) 1(r)=resistant, (s) =sensitive to Penicillin G.

The minimal concentrations required for inhibiting growth of thefollowing two gram negative bacterial strains in the agar incorporationtest are: Escherichia coli NCTC 86: 12.5 ,ag./ml.; Shigelia flexneriNCTC 8192: 3.12 ug/ml.

In an in vivo test albino mice were injected intraperitoneally withabout 350 million living Staphylococcus aureus bacteria of a highlyresistant strain (Geigy 5001). 69 mg./kg. of 2,6-diaminophenylpenicillin sodium, administered intramuscularly, cured half the animals(=CD The highest dosage of Penicillin G administered (400 mg./kg.) wasinelfective.

EXAMPLE 2 1.5 g. of 2,6-diaminobenzoic acid dihydrochloride aresuspended in ml. of acetone and 24 ml. of dioxan and then 2.8 ml. oftriethylamine and 0.86 ml. of chloroformic acid isobutyl ester are addedat about 3. After stirring for minutes at 0, the mixture is filtered andthe filtrate is added to a solution of 2.11 g. of triethyl ammonium6-amino-penicillanate in ml. of chloroform and 2 ml. of triethylamine.After stirring for 15 minutes at 0 and then for 45 minutes at 24, it isevaporated under water jet vacuum (12 torr), the oily residue isdissolved in 100 ml. of n-butanol and the solution is filtered. A slightexcess of the calculated amount of potassium a-ethyl caproate is addedto the yellow filtrate and, to enhance formation of precipitate, it isdiluted with anhydrous ether. 2,6-diaminophenyl penicillin potassiumgradually flakes out. It is separated from the mother liquor in acentrifuge and dried over phosphorus pentoxide in vacuo.

The grey powder, 0.82 g., shows the characteristic fi-lactam bands inthe IR spectrum (KBr) at 5.6514. Its antibiotic properties are similarto those of the product described in Example 1.

4 EXAMPLE 3 1.67 g. of p-nitrophenyl-Z,6-dinitrobenzoate, produced fromthe 2,6-dinitrobenzoyl chloride, described in Example l(a), aredissolved in 15 ml. of pure chloroform and the solution is addeddropwise to a solution, kept at 0, of 1.59 g. of triethyl ammonium6-amino-penicillanate and 0.6 ml. of triethylamine in 25 ml. ofchloroform. The whole is then stirred for 2 hours at room temperature.After concentrating in a rotary evaporator, the product is worked upanalogously to Example 1(b) and 2,6-dinitrophenyl penicillin sodium isobtained as a white amorphous powder.

The invention also concerns new antibacterial agents. These contain, asactive ingredient, 2,6-diaminophenyl penicillinic acid of Formula I orat least one nontoxic monobasic salt thereof in suitable form for oral,rectal, local or parenteral administration. Suitable nontoxic salts arethose with pharmacologically acceptable inorganic and organic bases,i.e., with bases the cations of which, in dosages at which the compoundsaccording to the invention are effective, have no physiological effectthemselves or have a beneficial action, particularly a local anaestheticaction in the case of parenteral administration. For example, the saltswith the bases mentioned hereinbefore can be used.

Dosage units for peroral administration preferably contain between 10%and of the acid of Formula I or of a nontoxic salt thereof. They areproduced by combining the active substance with, e.g., solid,pulverulent carriers such as lactose, saccharose, sorbitol, mannitol;starches such as potato starch, maize starch or amylopectin; alsolaminaria powder or citrus pulp powder; cellulose derivatives orgelatines, optionally with the addition of lubricants such as magnesiumor calcuim stearate or polyethylene glycols (Carbowaxes) of suitablemolecular weights, to form tablets or drage (sugar coated tablet) cores.The latter are coated, e.g., with concentrated sugar solutions which canalso contain gum arabic, talcum and/or titanium dioxide, or with alacquer dissolved in easily volatile organic solvents or mixtures ofsolvents. Dye-stuffs can be added to these coatings, e.g., todistinguish between various dosages of active substance.

Dosage units for rectal administration are, e.g., suppositories whichconsist of a combination of an acid of the general Formula I or of asuitable nontoxic salt thereof with a neutral fatty foundation, or alsogelatine rectal capsules which contain a combination of the activeingredient or a suitable salt thereof with polyethylene glycols(Carbowaxes) of suitable molecular weight.

Dry ampoules for the preparation of preferably 5-15% weight/volumeaqueous solutions for parenteral, particularly intravenous,intramuscular or subcutaneous administration, contain a water-solublenontoxic salt of the acid of Formula I, optionally together withsuitable stabilising agents and buffer substances.

Also ointrnents and powders can be used for the local treatment ofinfections. These forms of application can be prepared with thecarriers, diluents and additives conventionally used for this purpose.

The therapeutically active compounds according to the invention can beadministered in oral dosages as high as 300 mg.

The following nonlimitative examples illustrate the production oftablets and drages.

EXAMPLE 4 250 g. of 2,6-diaminophenyl penicillin or its sodium orpotassium salt are mixed with 175.80 g. of lactose and 169.70 g. ofpotato starch. The mixture is moistened with an alcoholic solution of 10g. of stearic acid and granulated through a sieve. After drying, g. ofpotato starch, 200 g. of talcum, 2.50 g. of magnesium stearate and 32 g.of colloidal silicon dioxide are mixed in and the mixture is pressedinto 10,000 tablets, each weighing 110 mg. and containing 25 mg. ofactive substance. If desired, the tablets can be grooved to permitcloser adaptation of the dosage.

EXAMPLE 5 A granulate is prepared from 250 g. of the active substanceused in Example 4, 175.90 g. of lactose and the alcoholic solution of 10g. of stearic acid. The granulate, after drying, is mixed with 56.60 g.of colloidal silicon dioxide, 165 g. of talcum, 20 g. of potato starchand 2.50 g. of magnesium stearate and pressed into 10,000 drage cores.These are then coated with a concentrated syrup made from 502.28 g. ofcrystallised saccharose, 6 g. of shellac, 10 g. of gum arabic, 0.22 g.of dye-stuff and 1.5 g. of titanium dioxide and dried. The dragesobtained each weigh 120 mg. and contain 25 mg. of active substance.

We claim:

1. An antibacterial pharmaceutical composition comprising anantibacterially effective amount of 2,6-diaminophenyl penicillin or apharmaceutically acceptable monobasic salt thereof and apharmaceutically acceptable carrm.

2. An antibacterial pharmaceutical composition according to claim 1,said composition being adapted for peroral administration and comprisinga solid pulverulent pharmaceutically acceptable carrier.

3. An antibacterial pharmaceutical composition according to claim 2wherein the sodium salt of 2,6-diaminophenyl penicillin is employed.

4. An antibacterial pharmaceutical composition according to claim 2wherein the potassium salt of 2,6-diaminophenyl penicillin is employed.

References Cited UNITED STATES PATENTS 2,951,836 9/1960 Doyle et a1.260-239.1

JEROME D. GOLDBERG, Primary Examiner

